http://www.fastcompany.com/1708463/fuji ... where-tech
Fujitsu just unveiled an "energy harvesting" device that can turn both heat and light into electrical power. Along with the company's self-powered medical devices, this hints at a future where power can be gleaned from everywhere.
Separate light- and heat-based systems for creating electrical energy--such as solar power and geothermal--have long been known. Fujitsu's trick is to combine the two ways of generating power into one device, leading to more efficient ways to gather energy from the environment, or what Fujitsu's calling "energy harvesting."